Differential electronic roll caliper



Feb. 16, 1965 P. HOLD 3,169,323

DIFFERENTIAL ELECTRONIC ROLL CALIPER 2 Sheets-Sheet 1 Filed May 31, 1961 Peler Hold BY wnan, QOM B MG Feb. 16, 1965 P. HOLD 3,159,323

DIFFERENTIAL ELECTRONIC ROLL CALIPER Filed May 31. 1961 2 Sheets-Sheet 2 320 El 440 0 350 430 80 40 3o 70 50 I30 zj q J:

I70 1 250 j 15.4230 I 2/0 $95.5. I H5312 *1 I g I;-\30 3/0 g 1 3 METER 30 W A520 230 ADD RANGE HMPUF/ER I n L53 '2 l -360 F at? 3 wk 88o g 4 350 INVENTOR woo 4/0 Pe+er Hold OSCILLHTOH ,2 0

SIGN/3L Z8 BY anflom/ QfNf/THTOR r/ at e 1 $6 ATTORNEYS United States Patent Ofi Fice Patented Feb. 16, 1965 This invention relates to roll calipers and more partic ularly to a roll caliper utilized in measuring the diameter of cylindrical surfaces such as paper mill rolls, shafts, bearings, crank pins and the like.

Heretofore, as described in United States Letters Patent No. 1,845,199, granted to C. F. Schnuck on February 16, 1932, the calipers conventionally in use comprise a cradle adapted to rest on a cylindrical surface to be measured, and having pivotally mounted thereon a pair of integrally formed graduated arms, each having a downwardly extending slide supported thereon with one arm provided with an indicator, such as a micrometer, and the other provided with a cooperating measuring point. As set out in the aforesaid patent, the cradle is adapted to rest on the surface for longitudinal movement thereon by means of four rolls which permit the rolling of the caliper unit along a cylindrical surface. In meas-' uring a cylindrical surface of a roll the measuring points are adjusted toward and away from the cradle simultaneeously with their adjustment toward and away from each other so as to dispose the measuring points at diametrically opposed points on the surface of the cylindrical object. In the measuring of cylindrical surfaces, such as rolls having a crown thereon, it is customary to roll the caliper along the roll to gauge the diameter of the roll at various points or to indicate the taper from one point to another.

Although the above-described calipers provide a convenient means for measuring the diameter of cylindrical surfaces they nevertheless suffer from the disadvantage of utilizing the direct translation of a mechanical movement train into a direct visual reading. Accordingly such calipers reflect the permissible and inherent tolerances of the various elements comprising the train which are consequently reflected in the visual readings resulting in a distinct disadvantage where extreme precision is required in the measurement of rolls.

Accordingly it is an object of this invention to provide a novel caliper eliminating the disadvantages of the prior art.

It is also an object of this invention to provide a novel caliper for measuring cylindrical surfaces, such as rolls, shafts and the like with precision. I lt'is a further object of this invention to provide a novel caliper adapted to translate dimensional variations of a cylindrical surface to a corresponding electrical signal which is converted into 'a visual reading.

Other objects and advantages will become more apparent from the following description and drawings in which PEG. l is an end view of a caliper in accordance with one embodiment of this invention mounted on a cylindrical surface;

PEG. 2 is an elevational view of the embodiment illustrated in PEG. 1; and

FIG. 3 is a schematic view illustrating an electronic circuit adapted to be employed in conjunction with the aforesaid embodiment.

Generally speaking, the invention comprehends a cradle or framework which rests upon a cylindrical surface by means of four rollers to permit rolling of the cradle along the top of the surface longitudinally thereof. Supported on the cradle in fixed radial relationship to the surface are a pair of integrally and downwardly extending to be actuated in response to dimensional variations of the cylindrical surface when the cradle is moved 1ongitudinally thereon so that the modifying means provides a corresponding modification of the signal of the emitting means. The modified signal from the emitting means is then converted by conventional translating means into a visual reading.

More specifically and by reference to the drawingsa cradle 18 or" substantially oblong form is adapted by means of four rollers 2% to rest on a cylindrical surface 13%, such as a roll to be measured, for longitudinal movement thereon. The rollers, which are mounted in pairs on corresponding longitudinal members 30 are located intermediate the ends of the cradle 10 to provide end portions of the cradle overhanging the rollers. Extending upwardly from the corresponding ends of the members 3% are a pair of cross pieces 46 and 56 having fixedly mounted therein a pair of parallel shafts 6i and 79v which are arranged so that their axes are parallel to the axis of a cylindrical object to be measured. The overhang of cradle 1% beyond rollers 2!) permits measuring of the end of the cylindrical surface without the necessity of bringing a pair of the rollers 20 to such an end as will be manifest hereinafter.

Slidably mounted on shafts 60 and 70 in a plane at right angles to the axes thereof is a cross-bar 80 which is adapted to be secured on the shaft by means of set screws 8 d and 166). The'cross-bar is mounted on the shafts by means of corresponding bores 11d and through which,

respectively, the shafts are inserted to dispose the crossbar in fixed radial relationship to the cylindrical surface to be measured, indicated at 13f). Extending downwardly from the corresponding ends of the, cross-bar'tlt are integral measuring arms 14% and 150 which may be arranged at an angle approaching 90 degrees and adapted to straddle the cylindrical surface to be measured. On arm 2 is a slide 160 to slide therealong. A similar slide 170 is provided on arm 1%. The slides 160 and 170 are provided with thumb screws and 19%, respectively, to secure the slides fixedly on their respective arms in any desired position of adjustment. Each of the arms is provided with lengthwise graduations while each slide mounted thereon is provided with an appropriate reference point or line for registering with the selected graduations of the arm. I

The function of the shaftstl and 79 is to fix the crossbar 8'5 and the integrally extending arms and in radial relationship to the cylindrical surface 130 in accordance with the preferred embodiment of this invention. However, it is to be understood that other equivalents providing this same function may be employed.

Slides ldil and 17d serve as amounting means to support thereon signal emitting means 206 and Eli), respectively, which have mounted therein signal modifying means 226 and 233, respectively, disposed in contact with substantially diametrically opposed points on the cylindrical surface 130 by means of adjustment of slides and 17% on the corresponding arms. The signal emitting means 2% and 21% are adapted for adjustable movement toward and away from each other by means of set-screws 240 and 250, respectively. In the preferred embodiment of this invention the signal emitting means Ztltl and 216 comprise'magnetic (FIG. 3) measuring heads 2-60 and 279, respectively, of the linear transducer type, well known in the art, to which an electrical signal is fed by means of an oscillating signal generator 2%. The signal received in each of heads 26% and 2765 is modified by Adjustably mounted on the arms is an;

' Wisual reading onia dial 339,

means of'jlinearly movable cores 2% iamplifier 31% with the amplified signal fed to a Conven .5

tional meter Sillfor converting To adjust theinstrument 'for the measurement of a ecific cylindrical. object, such as a roll, the caliper is set on the rolland the signal emitting means Zlltl and 216 are set onthe arms in accordance with the roll diameter Thereafter the emitting means Zlltl adjusted mechanically by means of set screw 24% directly toward or away f orn the roll with switch 34a (PEG; 3) closed until a reading is obtained somewhere on'the scale of dial 333%. The signal emitting means 218 is similarly adjusted by set screw; 25%) with "switchBSll closedand switch 34% open.

' Thereafter bothof the switches are closed and a reading ;-is obtained at the zero point of the indicator dial 333 by means of a zero setting knob 36%.

1 When the above-described adjustments have'been com pleted thecaliper is ready to indicate roll diameter changes asthecaliner is'mov'ed longitudinally back and forth along vthe length of the cylindricalobject. .As indicated above,

the receivedsignal to .011 the surface otthe roll followed by calibrating the 7 signal emitting means to the roll as described above.

It is pointed outthat the actual diameter of a roll'is not required to be measured ordinarily; instead it is the common practice in' the-art to measure only the change in roll diameter ja t successive points along the surface or face ofthe roll. However, it may be pointed out that the actual diameter can'be measured if a standard measure is introduced between the signal emitting means before the instrument is utilized for measuring the diameter of the roll in question. It is again pointed out that actual diameter is rarely necessary .1"

While a preferred embodiment of the, invention has been shown, it is to be understood that the same is not'to be limited to the specific details shown since the invention 7 is capable ofmodilication andvariation withinv the s irit andscop'eof the invention. Forfexample, although a pair oi signal emitting means have been described in the measurement of cylindrical objects, it is possible to utilise onl a's'in' le si nal emittin means when the measure-;

me'nt'ot surfacevariation isf desirecl only along a single longitudinal area'along'the surface of the cylindrical object. I L V Y Y 'Also,'tl1e' signal emitting means utilized in this invention may be comprised of conventional electrical resistor strain gauges which, as will beirecogni'zed, are conventionally employedfor modifying an electrical currentin response the dimensional variations of the surface of the cylindrical object actuates cores 2% and Ellllwithin their-respective" transducer'heads to modify-the signal "transmitted thereto and which is emitted-from the heads, amplified and sent to meter 32,0 for'visual translation on scale33tl. it has" 7 been found thatsince some of the-cylindrical objects or workpieces have acontourwhich is greater'than a normal rangecf the indicating dial 330, provision must be made 3 for compensation; Accordingly,'for'the measurement of such objects, use is made of add'range circuitryjcomprised of a series of-resistorsllitl, 389, 3%, dtltlland tld which areintroduced into the circuit successively one after theother, as requiredso as to add almownj increment to 'the original dial-reading. Electrically this involves subtractinga predetermined amount iromth e outputuof V to deflections induced time strain gauge.

, As noted above, although the invention has been described' with reference to aspecific embodiment, various modifications andchanges will be apparent to one skilled in the art, Theinventi'on'is,therefore, notto be limited by'sucli' an embodiment except as set forth in the ap:

pended claims.

Whatl claim is:

' [1. A caliper .f'or measuring 'the diameter of'cylin- "drical objects comprising 'a cradle, roller meansfor supporting ls-aid cradle on the surface of said object for moving said cradle longitudinally along thefsurface of the cylindrical-object, a pan of caliper armsfextending outwardly from said cradle and arranged to receive the Q object therebetw'een, and 'arinsup'po'rt rneans'mounted the "signal emittingrneansto bring the net output back I withinithe range ofthe indicator dial. r'lnjpractice, these additions are usuallysome 'small amount, such as (1.004; 0.005, or 0.010 inch depending uponthedegree of precisionincorporated in the electrical measuring components ofthelinstrurnent." it

Forconvenience the switches 34%- and 350Qtne fadd Y range"resistors,amplifier and the meter may be combined in asing'lechassis -iZOWhich may be mounted on a platform 43tlsecuredon the cross piecesflh' and 5t} and straddlingi cradleltl. In orderto facilitate measurement of the diaineterof a roll in a horizontalplane, a level 44% mayb'e 'rnount'eid on platfQr'm E-Sll to provide a' vis ual inv jdication of proper positioning of the" caliper onthe cylindricalsurface V 'In' operation of the caliber the slides 160 and 174 may be adjusted to measure j any part'icul'ar diameter by ad justing themto the appropriate, graduations provided on the extending larmsl ttl and 150, :Toadaptthe calipers" 'tomeasuringrolls'of such diameter the iangle between arms 140 andlSl) issue]; that the signal emitting means 200 .and210 are alwaysdisposedafl diametrically opposite points of a roll when the caliper is supported on Y Y and adjusted to the roll. In FIG. 1 the caliper {is' shown in two positions, one in full lines in which it is adjusted on said cradle and arranged to hold said arms in fixed radial relationship tothe surface ofithebbject, said suport means lon itudinall extendingbeyond said roller P D Y means at either end of said cradle, said arms being mov able longitudinally onsaid support means to positions beyond said roll'e'r means at either end of said cradle. n I, 2'. The caliper ofclaimfl' including surface engaging. means slidably and adjustably receivable on each of said arms to position said engagingmeansat' diametrical-y lYOPPOSCd points with rrespect'to the 'obiect. I

, tudinal movementalong theQaXis' thereqfifla pair ofcaliper 1 351%. caliperfor measuring the diameterflot a 'cylin- 'dric'al object 'cornpri'singfla cradle, roller means s1'ipport-' ing said cradle on detainee of thefl obiect 'for longiarmsl'disposed atc a fixed angle to eachjother': and exto the largest roll thatthecaliper is, capable of 'measur fi mg, and theotherjin broken lines in which it engages-the smallest roll. V

""Accordingly'when it is desired to measure rolls" o fdil.

' ferent diameters it is simply necessary to adjust the slides res and 17% along the arms 14% and lfitl so as to dispose the signal emitting meansjatdiametrically opposedpoints tending downwardly. fromQs'aidI cradlewith said arms '1 being arranged to "receive the object therebetwee'n, means mounting said-arms on said cradle'gin fixed i'adiallrelatmn {to the ob iecfl electric' signal generating.meansfmountedon "saidg'cradlqx signal modifying means, support means;

'for said' 'modifying means. slidably receivable n each of said arms-and adapted to dispose said modifying, V

means adjacent diametrically-'opposed points. on the object, said. modifying means including movable detectingfmeans' adapted' to contact. thejobje'ct .at said dia metric'ally opposedpointn said. detecting means be ng ,r'novable' in response to=surfacevariations in the object: 7 0;

upon" movement of said, cradlealong the object to; provide' for the emission of a modified-signal from said modifying means corresponding ito;the variations, and T anslating means for converting the modified signal to a 7 visual representation, said mounting. meansgextending eyond said roller means at either end ot'said cradle so that said caliper arms are movable longitudinally on said mounting means beyond said roller means at either end of said cradle.

References Cited in the file of this patent UNITED STATES PATENTS 5 Terry July 5, 1938 Aller July 26, 1949 Haines Dec. 23, 1952 Kroeger Mar. 25, 1958 Bowlby Mar. 10, 1959 Cannon Aug. 13, 1963 FOREIGN PATENTS Germany July 6, 1932 

1. A CALIPER FOR MEASURING THE DIAMETER OF CYLINDRICAL OBJECTS COMPRISING A CRADLE, ROLLER MEANS FOR SUPPORTING SAID CRADLE ON THE SURFACE OF SAID OBJECT FOR MOVING SAID CRADLE LONGITUDINALLY ALONG THE SURFACE OF THE CYLINDRICAL OBJECT, A PAIR OF CALIPER ARMS EXTENDING OUTWARDLY FROM SAID CRADLE AND ARRANGED TO RECEIVE THE OBJECT THEREBETWEEN, AND ARM SUPPORT MEANS MOUNTED ON SAID CRADLE AND ARRANGED TO HOLD SAID ARMS IN FIXED RADIAL RELATIONSHIP TO THE SURFACE OF THE OBJECT, SAID SUPPORT MEANS LONGITUDINALLY EXTENDING BEYOND SAID ROLLER MEANS AT EITHER END OF SAID CRADLE, SAID ARMS BEING MOVABLE LONGITUDINALLY ON SAID SUPPORT MEANS TO POSITIONS BEYOND SAID ROLLER MEANS AT EITHER END OF SAID CRADLE. 